Welcome to the forum @duplicated-paul
Interrupted backups due to a reboot explains how all of your original backup work “should” still be there, unless you deleted files. Did you notice files at the destination? If so, that data won’t be uploaded again. You might be seeing file scan, but deduplication feature is always there so it won’t upload a block twice.
Follow the links linked to that original post if you want to see other experiences or tips for doing this if it’s your initial backup. v184.108.40.206-220.127.116.11_experimental_2020-01-03 added a feature to “Stop after current file” which can be an alternative to doing initial uploads in small doses. I’d recommend it over the “Stop now” (which can get messy) or just restarting the PC (which might be worse). It’s hoped this will go Beta soon.